LIBRARY OF CONGRESS. 

(SMITHSONIAN DEPOSIT.) 

Chap. 4.5 

Shelf 

UNITED STATES OF AMERICA. 



Digitized by the Internet Archive 
in 2011 with funding from 
The Library of Congress 



http://www.archive.org/details/isfingalscaveartOOwhit 



Is Fingal's Cave Artificial? 

By F. COPE WHITEHOUSE, M.A. 




Staffa: View take.n fkom the top of a Cliff. 



Reprinted from 

THE POPULAR SCIENCE MONTH. 

DECEMBER, 1882. 






New York : D. APPLETON & CO., 1, 3, & 5 Bond Street. 



'.-T/eralr^y fr 



n'A**j. 



/J 




5- 5 



M* 



-4-v 



■ 



- "i 

9 



Head of Loch Fynb. 



IS FINGAL'S CAVE ARTIFICIAL?* 

By F. COPE WHITEHO.USE, M. A., etc. 

IN venturing to ask a question and thus imply a doubt upon a point 
on which geologists, statesmen, and poets have given their eon- 
sentient opinion lor a century, it is not without regret that an opin- 
ion, held without suspicion of challenge, should be subjected to criti- 
cism, and better proof than prescription required fur the title by which 
this celebrated cavern has been held and enjoyed as the work of 
Nature. 

The process of reasoning which led me to believe that the cavern 
owes its existence to the hand of man had little in common with the 
arguments by which the inference is now supported. In June, 1881, 
while examining the Giants' Causeway, it seemed evident that colum- 
nar basalt showed no tendency to erode and form hollows. Where 
the basalt, which for the height of some hundreds of feet above the 
chalk is quite amorphous, and caps the low promontories along the 
coast, is brought so low that more than one half of its thickness is im- 
mersed in the sea, the remainder projects above the water and forms 
the well-known natural pier. The caves on that coast are in the great 

* A summary of an address made before the American Association for the Advance- 
ment of Science at Montreal, August 30th, and the Academy of Science at New York, 
October 9, 1S82, illustrated by photographs and diagrams. 



ochre-bed or chalk. They are plaiuly artificial in their present form. 
The peculiar Gothic door-way and the sheltered approach strengthen 
the view that they bear a distinct relation to an ancient civilization, 
and that it is not by accident that adjacent cliffs are crowned with 
castles, neighboring mines were worked from unknown periods, beacon- 
rocks bear mythological names, and manuscripts refer to maritime 
expeditions to the Baltic and Mediterranean. It seemed antecedently 
possible that the same race, Kelto-Iberian, Wend, or Phoenician, which 
had formed harbors on the coast of Ireland, might also have been the 
active agent in that perforation which has been termed the most re- 
markable in Europe. This conjecture received strong and unexpected 
confirmation. It was submitted to rigid examination ; it was strength- 
ened by op])osition. It has been adopted, by a considerable number of 
eminent men, as a far stronger prima facie case than that commonly 
stated by the text-books in favor of marine erosion. If not well 
founded, it still suggests difficulties which have escaped observation, 
and may also correct the inaccurate terms in which Fingal's Cave has 
been described, and the imperfect representations which have gone 
far to perpetuate the hasty conclusion of Sir Joseph Banks. 

Fingal's Cave is not at the Giants' Causeway. It is in the southern 
end of the Island of Staffa, whose apparent size and position are neces- 
sarily exaggerated on the maps in common use. It is not " off the 

Bgcliti6gy-.f«ga^ / li-b.-'&^xg^ w 









4i STAF,FA/f"'A^' \JM %P-r.~ 



B&i 5 



vi *' <■' 

-#>3 Xandiiii riace B. 

■ *' s'' T' *> 






V7 ^oj....- .^.-t"-- — 9 ^.4-j£% 2 * - 9 / iS 

>-. 8 _ .,, ~'-'J3(-s«S.; 10 / «n. 

li "S 15 V4. i- ••.♦VTmi ' 

^^*%^ J7 

lOCaliTed 1 

\ i r— , m i wii i iirt l # i « iui l iiWHi ii r ' 

Fig. 1.— From the Admiralty Chart of Loch Tuadh. 

southwest coast of Scotland." It is deeply embayed in a large sinu- 
osity formed by the Island of Mull, and nearly inclosed on the opposite 
side by Iona and the Treshnish Islands. Beyond the latter a second 
line is drawn by Tiree and Coll, while to the north but to a greater 
distance are placed the islands of Minch, Rum, Eigg, and Canna. The 



circle is completely closed for :>l">° by land, distant at farthest from five 
to seven miles. From Dutchman's Cap, bearing nearly due west, to 
the " Stac"off Iona, there is comparatively deep water of forty to fifty 
fathoms. The charts, however, show that rocks approach the surface. 
"Five-Fathom Kock," " Dangerous Overfalls," and soundings of less 
than ten fathoms, push half-way across the Passage of Tiree. Mac- 
kenzie's Rock, which dries in four feet, guards the other entrance, 
and no Atlantic surge could pass into Loch Tuadh or the Sound of 
Iona, without changing its direction twice and almost at right angles. 
But Donegal receives the impetus of the tremendous billows which 
break against the steep cliffs of Mizen Head, or rush up the narrow 
gorges with which the exposed coast of the Northern Hebrides is so 
deeply scored. Staffa is singularly sheltered. It makes it antece- 
dently extremelv improbable that this particular spot would be selected 
by the ocean as a place on which to " prove its strength." Words- 
worth was both a landsman and a poet, and, as he says — 
" In a motley crowd, each the other's blight, 
Hurried and hurrying" — 

only san' it. His language, however, has undoubtedly been made a 
vehicle of scientific error. 

"Caves worn by the sea are due to the set of the currents, the 
force of the breakers, and the grinding of the shingle, which inevitably 
discover the weak places in the cliff, and leave caves as one of the re- 
sults of their work, modified in each case by the local conditions of the 
rock " (" Encyclopaedia Britannica "). Assuming that this is a com- 
plete statement of the law of marine erosion, how was FingaPs Cave 
"hollowed out of columnar basalt," and therefore rightly classed by 
Professor Boyd Dawkins, "among caves worn by the sea"? There is 
no current setting into this bay. The spring tides rise llf feet, neaps 
8 feet, and range 44 feet. The maelstrom of that part of the ocean 
is " where Corryvrechan's surges driven " make " the caldron of the 
spectral sea," but to the south, behind Colonsay. The force of the 
breakers is inconsiderable. Either they are the result of local disturb- 
ance formed to the east of Tiree, or the ground-swell and heaving of 
the sea after a storm. The island is fully protected by its own fore- 
shore. The perpendicular columns suggest an "unknown profundity 
of depth." But the basalt on the west is over 50 feet above the sea- 
level. A spit of conglomerated trap or tufa prolongs under water a 
Hat, rocky shore. There is a succession of rocks and shoals. The 20- 
fathom line is a mile distant, the 10-fathom half a mile, immediately 
followed by rocks, and 12, 15, and 9 feet of water. As the cave is in the 
southern face, it appears to be impossible, in the present state of the 
coast, that a wave with any momentum could strike directly upon that 
end of the island. As MacCulloeh sat on one of the columns, though 
the long swell raised the water at intervals to his feet, the movement 
was silent, and the surface of the sea apparently undisturbed. There is 




Fig. 2. — West Side of Staffa, 1463. G. W. W. Showing Arched Entrance to Cormorant's Cave. 



no shingle. The prismatic blocks are refractory. If a wave struck 
with sufficient force to dislodge the drums, or if, undermining the tuff, 
it strewed the beach with hexagonal or pentagonal blocks, these smooth 
stones, with polished sides, buried in the finer material, would offer 
very great resistance to any further waste of the cliff. Although a 
channel of 18 feet at mean low water approaches and enters the cave, 
there is no ledge over which the material could have been carried. 
The sharp conchoidal fracture would not serve the purpose of such 
crystalline rocks as quartz or granite, and furnish the fluid wave with 
a serrated edge. 

The cave is not formed in what would naturally be considered the 
cliff ; least of all in its weakest place. After examining the Admiralty 
Chart, " the reader will, no doubt, pass with pleasure to the rich de- 
scription by Dr. MacCulloeh." That author, however, says that the 
whole of Fingal's Cave seemed like a ship heaving in a sea-way, and 
therefore his survey may be considered less trustworthy than that of 
Commanders Bedford and Creyke (Admiralty Chart, 1857). It seems in- 
correct to say, " The caves are so numerous that they may be said to per- 
forate at brief intervals the whole face of the island ; but those which 



occur on the south [sic, query west) and the north sides are remark- 
able neither for beauty nor for magnitude." The eaves are sufficiently 
numerous t<> furnish an argument. There are very few hollows worn 
by the sea in the Scotch coast. The islet, which contains a dozen, has 

not the j,,,, 1 part of the indented line of the mainland, and bears an 

infinitesimal ratio to the sea-board, including the islands. Its parent, 
Mull, within whose bosom rests this irregularly oval rock, "measuring 
about one and a half mile in circumference," has in the dimension of 
length one hundred and fifty times better right to a "museum of won- 
ders." The " Isle of Columns " is a speck too tiny to show on any 
ordinary map. The chance that it would contain, as a legitimate yet 
exceptional result of normal contact between igneous rock and sea- 
water agitated by wind, "the most remarkable cave in Europe," is less 
than 0. It is the / — 1. 

The uneven table-land is formed of " three distinct beds of rock of 
unequal thickness, inclined toward the east at an angle of about nine 
degrees. The lowest is a rude trap tufa, the middle one is divided 
into columns placed vertically to the plane of the bed, and the upper- 
most is an irregular mixture of small columns and shapeless rock." 
The columnar bed is never more than 60 feet thick. The island itself 
attains a maximum height of 129 feet. It has no peak from which 
rain-water might descend in a considerable quantity. There is no 
series of fissures corresponding to the perforations. There is nothing 
on the flat top to suggest the tunnels beneath. Proceeding toward 
the south from the landing-place, there are six eases of alleged erosion, 
each presenting its own seemingly insuperable difficulty, and cumula- 
tively requiring a more thoughtful and serious consideration than the 
fantastic phrases in which 'stupendous (!) columns, three feet thick 
and thirty feet high, rise from a (lark-red or violet-colored rock over 
which tin on mi rolls, and reflects from its whiti bottom a variety of 
crimson and yellow? 

It appears now to be well established that the peculiar structure 
of columnar basalt is due to contraction and splitting consequent upon 
cooling. The analogy is rather to the splitting often seen in the mud 
bottom of a dried-up pool than to ordinary crystallization. The vari- 
ous conditions point to the contractile origin of the structure, at the 
same time that the result suggests a curious mimicry of imperfect 
crystallization. If the cooling mass of basalt be in one of its vertical 
sections of such a form that successive isothermal couches, taken in 
descending order, are not parallel to the original cooling surface, 
as they are in all cases of straight ami parallel prisms, but divergent 
gradually from the cooling surface and from each other, then the lines of 
the splitting of the prisms, always true to these couches, must be curved 
in one direction. This will be true, whether the isothermal couches be 
plane surfaces divergent from a thinner to a thicker part of the mass, 
or whether they be curved surfaces arising from the mass reposing on 



a curved bottom and diverging in like manner. The crux of Staffa is ' 
Scallop or Clamshell Cave. Inattention has caused the various authors 
to describe it as if there was nothing astonishing in the sudden inter- 
ruption of the columns, which are " bent so as to form on one side a 




series of ribs not unlike an inside view of the timbers of a ship,' 1 while 
" the opposite wall is formed by the ends of columns, and bears a gen- 
eral resemblance to the surface of a honey-comb." Sixteen feet wide, 



130 feet long, how could the sea attack the landward, southeast end, 
ninl carve a trench 15 to •"><> feet deep, where it is geologically impos- 
sible that a "fault" or "weak place" aided the natural force? The 
channel of Bouchaillie, seen from the cliff above, is a canal cut through 
the columnar basalt, and taking a slice from that conoidal pile of 
columns about thirty feet high, which is seen a few yards to the right 
of the Colonnade and Fingal's Cave. Where is the debris ? Why 
should it be crossed at right angles by the passage leading into the 
Clamshell Cave ? The Causeway here presents an extensive surface, 
which terminates in a long, projecting point at the eastern side of the 
Croat Cave. It is formed normally. The heads of columns show in 
a compact and serried phalanx. Bach row protects the other in turn. 
The tesselated pavement, as on the Irish coast, is a firm, impenetrable 
mas3, showing by its steepness its utter contempt for the wavelets 
which could not break those ranks in a geological aeon. There is 
nothing to prepare the scientific mind, distrustful of abrupt changes, 
for the adjacent excavation. Its dimensions are, from the top of the 
arch to the cliff above, 30 feet ; to the water, 6(5 feet ; to the bottom, 
88 feet. Its breadth of 42 feet continues to within a small distance 
of the inner extremity, when it is reduced to 22 feet. The total 
length is 22? feet. 

It is usually said to have been formed by erosion at the base. The 
columns, falling, dragged down a part of the roof, aided by a fissure 
which divides the ceiling. The tuff is not eroded even at the south- 
west end of the island. These pillars, however strong and enduring, 
are each composed of many separate joints or pieces, built tip one upon 
another. They do not adhere in any way together, but merely rest 
mechanically upon each other, and are easily detachable. The capitals 
beyond cling to the roof. There is no fissure. In Boat Cave, tuff is 
undermined for 1,800 square feet, yet the columns stand wedged across 
12 feet of width. At Tanaga Island, in the Aleutian group, the broken 
columns form a slightly convt c roof across an opening 20 feet wide. 
No such Gothic arch was ever formed by Nature. It is strikingly 
Phoenician. No natural cave has an entrance higher than the interior. 
A tidid or earthquake wave would not reach the top of the arch. The 
cave is post-glacial. The upheaval of that part of Scotland is put at 
25 feet. It would not bring the confused basalt within reach of the 
waves. Their bleaching power is easily calculated. It is determined 
in this case by the frail wall to the east. For a merciless ocean select- 
ing this victim of his fury, and 

" Down-bearing with his whole Atlantic weight 
Of tide and tempest on the structure's bnsej" 

and " flashing to that structure's topmost height," in his blind frenzy 
would have swept through the loose drums to the right. Montalemhert 
thought it far inferior to any cathedral, or even a monastic church 
such as Cluny or Yezelay. If "raising (!) a minster," it would have 



10 

been better to put all the chapels under one roof. The horizontal and 
perpendicular sections are equally at variance with the curved surface 
formed bv a fluid in vibration. The columnar basalt would form a 




curved and not a rectangular water-line. What other cavern has a 
uniform breadth from the 023ening, and five and a half diameters in 
length ? 

Cormorant's or Mackinnon's Cave is easy of access, and terminates 



11 

in a "gravelly" beach, where a boat may be drawn up. It is 50 feet 
high, -1* feet broad, and ~l'!l feet lung-. It is excavated in the lower 
Stratum. Thus two tunnels of the same dimensions are supposed to 
have been driven into two different materials by the same force. The 
interim- dimensions are nearly the same to the end. As no sentimental 
or religious motive can be assigned to Nature for this freak, it is amen- 
able to comparison. The Blue Grotto of Capri is typical. Its entrance 
is scarcely three feet in height ; in the interior the roof rises to a 
height of 41 feet ; the water is 8 fathoms deep ; length of the grotto, 




(.'AVE (LOOKING OUT), SHOWING IoNA 



175 feel ; greatest width, 100 feet. Here the great siz.e of the aper- 
ture is further increased. The superior part of the front, penetrating 
into the columnar basalt, has hollowed a recess above the main open- 
ing. The same Gothic tympanum, distorted by the material, not only 
marks its artificial origin, but disproves the allegation that the col- 
umns could not form a natural architrave. The Boat Cave is acces- 
sible only by sea. It is a long opening, resembling the gallery of a 



12 

mine, excavated also in the tuff. Its height being about 16 feet (above 
the sea'?), its breadth 12, and its depth about 150, it offers, in its pro- 
portion of twelve and a half diameters, the greatest contradiction to 
all other instances of sea-worn homogeneous rock. 

But not only do Cormorant's and Fingal's Cave, each protected by 
its breakwater, face the adjacent land and not the open sea, and that 
land the far-famed Island of Iona, center of art and civilization, "dear 
to Christendom for more than a thousand years," but from the end of 
this deep cavity, to which a boat may sail in any ordinary weather, the 
" Dun " or Hill of " Hy " or Iona rises against the sky, in the middle 
of the arc of a few degrees subtended by the grand doorway. Until 
it is shown that a thousand yards of landlocked, iron-bound coast can 
be cut and tunneled in utter disregard of every known law of mechan- 
ical action, the caves in Staffa, on the west coast of Scotland, driven 
into igneous rock, not modified by local conditions, or in the weak 
places " of an exposed cliff," can not be classified as merely remarkable 
instances'of caves worn by the sea. Had the learned duke who com- 
menced his description of Iona with these words, " No two objects of 
interest could be more absolutely dissimilar in kind than the two 
neighboring islands of Staffa and Iona," " mixed Celtic memories with 
the Phrygian mount," recalled Athos, Tyre, and Carthage, or even the 
twin Island of Lerins, he might have hesitated to put them in sharp 
antithesis to say that only an accident of geography could unite their 
names, or with " the mighty surge " of personal and social authority 
drowned the faint cry for relief which reached his ears, and declined 
even to consider the solution here offered of a problem whose com- 
plex factors he had so forcibly stated. 



From "THE EARTH AND ITS INHABITANTS." 




The Exterior of Fjxgal's Cue. 



D. APPLETON & CO., NEW YORK. 



■fk-\ 



Mud'/ 







Glesmoee. 



LIBRARY OF CONGRESS ( 



029 708 066 I 



i 










